The present invention relates to a liquid distributor for distillation columns, of the type comprising a principal volume having in its lower portion outlet openings distributed about a region.
Floating petroleum platforms produce residual gases. For environmental and economic reasons, it is more and more necessary to recover these gases. One method consists in their conversion to heavier hydrocarbons, in the form of liquid and hence more easily transportable, by the Fischer-Tropsch process, which consumes large quantities of oxygen.
It would be interesting to be able to provide an on-board air distillation column on a floating platform or a barge, but the good operation of such equipment is burdened with serious difficulties. Thus, a first requirement is that the liquid be uniformly distributed at the head of the column over all the cross section of this latter despite the swinging of its axis due to swell.
The invention has for its object to provide a liquid distributor whose operation will be less sensitive to such oscillations.
To this end, the invention has for its object a liquid distributor of the recited type, characterized in that it comprises a transport member adapted to transmit by gravity the liquid from at least one opening in the perforated bottom to a supply point not located in vertical alignment with this opening.
The distributor according to the invention can comprise one or several of the following characteristics:
the opening is constituted by a single perforation or by several perforations adjacent each other;
the transport member comprises an inlet end located below and in vertical alignment with said opening and spaced from the outlet end of this latter;
the transport member comprises an upwardly open conduit in the form of a trough or closed in the form of a tube, this conduit being straight, bent at one or several locations or curved;
the transport member comprises at its outlet end a spray device for a spray region whose area is greater than that of said opening;
the mean diameter of said region is less than the mean diameter of the surface containing the outlet openings of the transport members, the ratio of the diameters being particularly about 1 to 6;
the distributor comprises transport member associated with a group of openings spaced from each other and adapted to carry the liquid flow from these openings substantially to a common supply point not located in vertical alignment with said openings;
the transport member comprises several conduits, particularly several tubes, whose inlets are adapted to receive the liquid flow from said openings, these conduits joining in a single conduit for the group of openings;
the total flow rate of said flow remains substantially constant when the distributor inclines;
the transport member or members associated with two openings substantially diametrically opposed relative to a central axis of said region and of the same area, lead substantially to a common supply point;
the liquid flow from at least one opening or group of openings is carried by the transport member or members such that its flow rate becomes greater when the sprayed region is raised under the influence of the inclination and less in the contrary case;
the transport member associated with each opening leads to a supply point situated angularly at an angle of 180xc2x0 from this opening relative to a central axis of the distributor;
the openings are disposed in a first substantially horizontal plane in concentric substantially circular crowns each corresponding to a crown of outlet openings disposed in a second substantially horizontal plane located below the first plane and comprising the same number of supply points, and a transport member connected to each point of the first crown at a point associated with the second crown;
the couples of associated points are offset angularly by a same angle about the axis of the crowns, the transport member connecting two crowns forming an envelope surface in the shape of a sleeve and the assembly of the transport members forming a series of such envelope surfaces nested within each other;
said angular offset is reversed from one envelope surface to the following;
said angular offset is comprised between about 80 and 100xc2x0;
said angular offset is comprised between about 100 and 180xc2x0;
the outlet ends of the transport members supply the liquid to several secondary distribution receptacles with perforated bottoms.
The invention also has for its object a distillation column characterized in that it comprises, at at least one level, a liquid distributor as defined above, above a distillation section.
According to other characteristics of this distillation column:
the distillation section has cross-corrugated packing;
the distributor is a distributor at the head of the column, said principal volume being at least partially disposed within the upper dome of this latter;
the transport members deliver directly the liquid onto the distillation section;
the column is on-board a floating structure such as a floating petroleum platform or a barge.